One of the primary safety problems facing persons operating electric pressing irons involves the fact that the iron, if left unattended can constitute a fire or safety hazard to children. In the past a number of schemes have been developed to interrupt power to an electric heating element of a pressing iron in the event that the iron is not being used.
Recently an electronic pressing iron was developed which has a motion and attitude sensing circuit which terminates a flow of electric power to the heating element when the pressing iron is positioned with its soleplate horizontal and not moving for a period of thirty seconds. That electronic pressing iron is disclosed in a U.S. patent application, Ser. No. 605,442, filed Apr. 27, 1984, entitled ELECTRONIC PRESSING IRON and assigned to the same assignee as this application.
That electronic pressing iron also has the ability to interrupt electric power to the electric heating element when the pressing iron is positioned with its soleplate in a substantially vertical plane or is resting on its heel rest for a period of ten minutes.
Thus, it may be appreciated that when the pressing iron has its soleplate in the lowered or horizontal position electric power is quickly interrupted if the pressing iron is not being moved in order to prevent damage to fabrics upon which the iron may be resting and to avoid the likelihood of fire.
Similarly, when the pressing iron was positioned in the soleplate raised position, electric power was interrupted to the heating element after a ten minute period in that position to allow the soleplate to cool down.
One of the drawbacks of that electronic pressing iron lies in the fact that the circuit required to perform the motion and attitude sensing functions is relatively bulky, portions of it being located in the handle of the pressing iron, ard other portions being located in a heel rest cavity within the pressing iron. That construction requires numerous electrical leads which connect the circuits in the handle to the circuits in the heel rest to be threaded through the back of the pressing iron, leading to significantly increased production costs over those found in a conventional pressing iron. In addition, the switching device which controls the electric power flowing to the heating element comprises a direct current relay which is relatively expensive and bulky. Additional power handling circuits are required to convert the alternating line current which the pressing iron receives to direct current so that the direct current relay may be employed in the circuit.
Thus there is a need for a low cost compact circuit which may be substantially enclosed within the handle portion of the pressing iron away from the heel rest portion where the circuit may be exposed to moisture. What is also needed is an electronic pressing iron which can interrupt power to its heating element after a relatively brief period in which the soleplate is stationary and horizontal and which can interrupt power to its electric heating element after a longer period when the soleplate is in a substantially vertical plane.